RFPID: development and 3D-printing of a female physical phantom for whole-body counter.

Whole-body counters (WBC) are used in internal dosimetry forin vivomonitoring in radiation protection. The calibration processes of a WBC set-up include the measurement of a physical phantom filled with a certificate radioactive source that usually is referred to a standard set of individuals determined by the International Commission on Radiological Protection (ICRP). The aim of this study was to develop an anthropomorphic and anthropometric female physical phantom for the calibration of the WBC systems. The reference female computational phantom of the ICRP, now called RFPID (Reference Female Phantom for Internal Dosimetry) was printed using PLA filament and with an empty interior. The goal is to use the RFPID to reduce the uncertainties associated within vivomonitoring system. The images which generated the phantom were manipulated using ImageJ®, Amide®, GIMP®and the 3D Slicer®software. RFPID was split into several parts and printed using a 3D printer in order to print the whole-body phantom. The newly printed physical phantom RFPID was successfully fabricated, and it is suitable to mimic human tissue, anatomically similar to a human body i.e., size, shape, material composition, and density.

Development of shielding evaluation and management program for O-ring type linear accelerators.

The shielding parameters can vary depending on the geometrical structure of the linear accelerators (LINAC), treatment techniques, and beam energies. Recently, the introduction of O-ring type linear accelerators is increasing. The objective of this study is to evaluate the shielding parameters of new type of linac using a dedicated program developed by us named ORSE (O-ring type Radiation therapy equipment Shielding Evaluation). The shielding evaluation was conducted for a total of four treatment rooms including Elekta Unity, Varian Halcyon, and Accuray Tomotherapy. The developed program possesses the capability to calculate transmitted dose, maximum treatable patient capacity, and shielding wall thickness based on patient data. The doses were measured for five days using glass dosimeters to compare with the results of program. The IMRT factors and use factors obtained from patient data showed differences of up to 65.0% and 33.8%, respectively, compared to safety management report. The shielding evaluation conducted in each treatment room showed that the transmitted dose at every location was below 1% of the dose limit. The results of program and measurements showed a maximum difference of 0.003 mSv/week in transmitted dose. The ORSE program allows for the shielding evaluation results to the clinical environment of each institution based on patient data.

Managing radiation safety and protection in gastroenterology in Japan: insights from the REX-GI study.

Fluoroscopy-guided gastrointestinal procedures, including gastrointestinal stenting, balloon-assisted endoscopy (BAE), endoscopic retrograde cholangiopancreatography (ERCP), and endoscopic ultrasound (EUS), are essential for diagnosis and treatment in gastroenterology. Such procedures involve radiation exposure that necessitates strict safety measures to protect patients, doctors, and medical staff. The April 2020 update to Japan's Ionizing Radiation Injury Prevention Regulations for occupational exposure reduced the lens exposure dose limit to approximately one-seventh of its previous level. This change highlights the need for improved safety protocols. Without adaptation, the sustainability of fluoroscopy-based endoscopic techniques could be at risk due to the potential to exceed these new limits. This review examines the current state of medical radiation exposure in the field of gastroenterology in Japan and discusses the findings of the REX-GI study.

Occupational orthopedic problems and its relation to personal radiation protection in interventional radiology.

PURPOSE: Several studies report occupational orthopedic problems among interventional cardiologists. These health problems are usually multifactorial. However, the personal protective equipment used should play a major role. An online survey was conducted to determine the frequency of such health problems among interventional radiologists and to correlate them with the use of personal radiation protective clothing. MATERIAL AND METHODS: An anonymous online survey that comprised of 17 questions was sent via e-mail to 1427 members of the German Society for Interventional Radiology (DeGIR) in Germany, Austria and Switzerland. The questions were focused on interventional workload, the use of personal radiation protection apparel and orthopedic problems. Given the different scale levels, the associations between the variables were analyzed using different statistical methods. A significance level of p < 0.05 was chosen. RESULTS: There were 221 survey responders (15.5% response rate). About half of responders (47.7%) suffered from more than five episodes of orthopedic problems during their interventional career. Lumbar spine was involved in 81.7% of these cases, cervical spine in 32.8%, shoulder in 28.5% and knee in 24.7%. Because of orthopedic problems, 16.1% of the responders had to reduce and 2.7% had to stop their interventional practice. The number of affected body regions correlates with the fit of the radiation protection means (p < 0.05, r = 0.135) and the reduction of activity as an interventional radiologist (p < 0.05, r = -0.148). CONCLUSION: Overall, the survey reveals widespread orthopedic problems at several body regions among interventional radiologists, associated with the fit of radiation protection systems, among other factors. A connection between the orthopaedic complaints and the radiation protection system used could not be established.

Potential risk assessment: a model for quality evaluation in fluoroscopy-guided interventional procedures.

This study presented a model applied for potential risk assessment in an interventional radiology setting. The model of potential risk assessment (MARP) consisted of the creation of a scale of indicators ranging from 0 to 5. The radiation levels were categorized according to gender, kind of procedure, value of kerma air product (Pka), and accumulated radiation dose (mGy). The MARP model was applied in 121 institutions over 8 y. A total of 201 656 patient radiation doses (Dose-area product and accumulated kerma) data were launched into the system over time, with an average of 22 406 doses per year. In the context of the workers (cardiologists, radiographers, and nurses) monitored during the MARP application, 8007 cases (with an average of 890 per year) of occupational radiation doses were recorded. This study showed a strategy for quality evaluation in fluoroscopy using a model with a compulsory information system for monitoring safety.

Secondary proton buildup in space radiation shielding.

The risk posed by prolonged exposure to space radiation represents a significant obstacle to long-duration human space exploration. Of the ion species present in the galactic cosmic ray spectrum, relativistic protons are the most abundant and as such are a relevant point of interest with regard to the radiation protection of space crews involved in future long-term missions to the Moon, Mars, and beyond. This work compared the shielding effectiveness of a number of standard and composite materials relevant to the design and development of future spacecraft or planetary surface habitats. Absorbed dose was measured using Al2O3:C optically stimulated luminescence dosimeters behind shielding targets of varying composition and depth using the 1 GeV nominal energy proton beam available at the NASA Space Radiation Laboratory at the Brookhaven National Laboratory in New York. Absorbed dose scored from computer simulations performed using the multi-purpose Monte Carlo radiation transport code FLUKA agrees well with measurements obtained via the shielding experiments. All shielding materials tested and modeled in this study were unable to reduce absorbed dose below that measured by the (unshielded) front detector, even after depths as large as 30 g/cm2. These results could be noteworthy given the broad range of proton energies present in the galactic cosmic ray spectrum, and the potential health and safety hazard such space radiation could represent to future human space exploration.

Society and Nuclear Energy: What Is the Role for Radiological Protection?

ABSTRACT: The harm that society expects from ionizing radiation does not match experience. Evidently there is some basic error in this assumption. A reconsideration based on scientific principles shows how simple misunderstandings have exaggerated dangers. The consequences for society are far-reaching. The immediate impact of ionizing radiation on living tissue is destructive. However, this oxidative damage is similar to that produced during normal metabolic activity where the subsequent biological reaction is not only protective but also stimulates enhanced protection. This adaptation means that the response to oxidative damage depends on past experience. Similarly, social reaction to a radiological accident depends on the regulations and attitudes generated by the perception of previous instances. These shape whether nuclear technology and ionizing radiation are viewed as beneficial or as matters to avoid. Evidence of the spurious damage to society caused by such persistent fear in the second half of the 20 th century suggests that these laws and attitudes should be rebased on evidence. The three stages of radiological impact-the initial physical damage, the subsequent biological response, and the personal and social reaction-call on quite different logic and understanding. When these are confused, they lead to regulations and public policy decisions that are often inept, dangerous, and expensive. One example is when the mathematical rigor of physics, appropriate to the immediate impact, is misapplied to the adaptive behavior of biology. Another, the tortured historical reputation of nuclear technology, is misinterpreted as justifying a radiological protection policy of extreme caution.Specialized education and closed groups of experts tend to lock in interdisciplinary misperceptions. In the case of nuclear technology, the resulting lack of independent political confidence endangers the adoption of nuclear power as the replacement for fossil fuels. In the long term, nuclear energy is the only viable source of large-scale primary energy, but this requires a re-working of public understanding.

Replace the Linear No-threshold Model with a Risk-informed Targeted Approach to Radiation Protection.

ABSTRACT: The linear no-threshold (LNT) model may be useful as a simple basis for developing radiation protection regulations and standards, but it bears little resemblance to scientific reality and is probably overly conservative at low doses and low dose rates. This paper is an appeal for a broader view of radiation protection that involves more than just optimization of radiation dose. It is suggested that the LNT model should be replaced with a risk-informed, targeted approach to limitation of overall risks, which include radiation and other types of risks and accidents/incidents. The focus should be on protection of the individual. Limitation of overall risk does not necessarily always equate to minimization of individual or collective doses, but in some cases it might. Instead, risk assessment (hazards analysis) should be performed for each facility/and or specific job or operation (straightforward for specialized work such as radiography), and this should guide how limited resources are used to protect workers and the public. A graded approach could be used to prioritize the most significant risks and identify exposure scenarios that are unlikely or non-existent. The dose limits would then represent an acceptable level of risk, below which no further reduction in dose would be needed. Less resources should be spent on ALARA and tracking small individual and collective doses. Present dose limits are thought to be conservative and should suffice in general. Two exceptions are possibly the need for a lower (lifetime) dose limit for lens of the eye for astronauts and raising the public limit to 5 mSv y -1 from 1 mSv y -1 . This would harmonize the public limit with the current limit for the embryo fetus of the declared pregnant worker. Eight case studies are presented that emphasize how diverse and complex radiation risks can be, and in some cases, chemical and industrial risks outweigh radiation risks. More focus is needed on prevention of accidents and incidents involving a variety of types of risks. A targeted approach is needed, and commitments should be complied with until they are changed or exemptions are granted. No criticism of regulators or nuclear industry personnel is intended here. Protection of workers and the public is everyone's goal. The question is how best to accomplish that.

Updating national diagnostic reference levels for computed tomography in Greece: Challenges on patient protection optimisation.

The escalating use of Computed Tomography (CT) imaging necessitates establishment and periodic revision of Diagnostic Reference Levels (DRLs) to ensure patient protection optimization. This paper presents the outcomes of a national survey conducted from 2019 to 2022, focusing on revising DRLs for adult CT examinations. Dosimetric data from 127 scanners in 120 medical facilities, representing 25% of the country's CT scanners, were collected, emphasizing geographic distribution and technology representation. Τhe parameters used for DRLs were the CTDIvol and the DLP of a typical acquisition of the region of interest (scan DLP). In addition to the 7 CT examination for which the DRL values were revised, establishment of DRLs for neck, cervical spine, pelvic bones-hips, coronary artery calcium (Ca) score and cardiac computed tomography angiography (CCTA) examinations was performed. Revised DRLs exhibited a 15 % average decrease in CTDIvol and a 7 % average decrease in scan DLP from the initial DRLs. This reduction of dosimetric values is relatively low compared to other national studies. The findings revealed wide variations in dosimetric values and scan lengths among scanners, emphasizing the need for standardization and optimization. Incorporation of advanced technologies like Iterative Reconstruction (IR) showcased potential for further dose reduction, yet challenges in uniform implementation persist. The study underscores the importance of ongoing optimisation efforts, particularly in the context of increased CT utilization and evolving technology. The revised DRLs have been officially adopted in Greece, emphasizing the commitment to safe and effective CT practices.

Occupational dose measurement in interventional cardiology practice.

Ensuring the safety of healthcare workers in interventional cardiology necessitates effective monitoring of occupational radiation exposure. This study aims to assess the accuracy of the over-apron single dosimetric approach compared with double dosimetric methods and explore the relationship between under-apron and over-apron doses. This investigation showed that the prescribed annual dose constraint of 20 mSv year-1 was not exceeded by the maximum annual occupational doses determined by dosimetric algorithms, which were 0.13 ± 0.02, 0.15 ± 0.02 and 0.27 ± 0.04 mSv, respectively. The study demonstrated excellent statistically significant correlations among single and double dosimetric algorithms and between direct under-apron and over-apron doses. Consequently, single dosimetric algorithms could effectively estimate doses for double dosimetric algorithms, highlighting the limited added value of under-apron measurements. These findings significantly impact the practice of interventional cardiology in Sri Lanka, playing a crucial role in enhancing radiation protection measures.

Estimation of internal-exposure contribution in radiation dose exposure for boron neutron capture therapy.

Although boron neutron capture therapy (BNCT) causes minor damage to normal cells owing to the nuclear reactions induced by neutrons with major elements of tissues such as hydrogen and nitrogen, it is useful to estimate the accurate exposure dose for radiation protection. This study aims to estimate the contribution of internal exposure in radiation exposure dose for BNCT. The study was performed by referring to clinical studies at a reactor-based BNCT facility on the basis of computational dosimetry. Five irradiation regions of head and neck were selected for the estimation. The results suggest that external exposure occurred primarily in and around the irradiation field. Furthermore, during the exposure dose estimation in BNCT, internal exposure was found to be not negligible, implying that the irradiation regions in treatment planning must be considered for avoiding damage to certain critical organs that are susceptible to internal exposure.

Characterizing imaging radiation risk in a population of 8918 patients with recurrent imaging for a better effective dose.

An updated extension of effective dose was recently introduced, namely relative effective dose ( E r ), incorporating age and sex factors. In this study we extended E r application to a population of about 9000 patients who underwent multiple CT imaging exams, and we compared it with other commonly used radiation protection metrics in terms of their correlation with radiation risk. Using Monte Carlo methods, E r , dose-length-product based effective dose ( E DLP ), organ-dose based effective dose ( E OD ), and organ-dose based risk index ( RI ) were calculated for each patient. Each metric's dependency to RI was assessed in terms of its sensitivity and specificity. E r showed the best sensitivity, specificity, and agreement with RI (R2 = 0.97); while E DLP yielded the lowest specificity and, along with E OD , the lowest sensitivity. Compared to other metrics, E r provided a closer representation of patient and group risk also incorporating age and sex factors within the established framework of effective dose.

Radioprotection issues in uraniferous minerals collections with reference to an actual case.

Our work investigated the radioprotection implications associated with the possession of a collection of uraniferous minerals. Considering different scenarios, we developed (and applied to an actual collection) specific formulas for radiation doses evaluation. We discussed the shielding necessary to reduce the gamma irradiation down to the required values. A mathematical model was developed to estimate the minimum air flow rate to reduce the radon air concentration below the reference values. The radiation risks associated to the handling of single specimens was also addressed, including hand skin irradiation and shielding capabilities of surgical lead gloves. Finally, we discussed the radiation risks associated to the exhibition of a single specimen. The results, compared to the safety standards of the EU Directive 13/59, show that the exhibition of uraniferous samples with activity of a few MBq do not need specific radioprotection requirements nor for the involved personnel nor for visitors.

Phantom study of a self-shielded X-ray bone age assessment instrument against scattered radiation in children.

Hand-wrist radiography is the most common and accurate method for evaluating children's bone age. To reduce the scattered radiation of radiosensitive organs in bone age assessment, we designed a small X-ray instrument with radioprotection function by adding metal enclosure for X-ray shielding. We used a phantom operator to compare the scattered radiation doses received by sensitive organs under three different protection scenarios (proposed instrument, radiation personal protective equipment, no protection). The proposed instrument showed greater reduction in the mean dose of a single exposure compared with radiation personal protective equipment especially on the left side which was proximal to the X-ray machine (≥80.0% in eye and thyroid, ≥99.9% in breast and gonad). The proposed instrument provides a new pathway towards more convenient and efficient radioprotection.

Factors Affecting Gonadal Shielding Use Among Technologists in California.

PURPOSE: To assess the patient gonadal shielding practices of radiologic technologists in the state of California. METHODS: A survey invitation was sent via email to registered radiologic technologists in California to collect data to determine whether there were significant associations between gonadal shielding practices and various categorical variables, including patient sex, patient age, body part, availability of gonadal shielding protocols, availability of gonadal shields, and supervisor encouragement. RESULTS: There was a significant association between gonadal shielding protocol availability and supervisor encouragement of using gonadal shielding (P = .005) and between gonadal shielding availability and supervisor encouragement of using gonadal shielding (P < .001). Contrary to other studies in the literature, there was a significant difference between patient sex and the likelihood of gonadal shielding use, with participants indicating that they shield girls and women more often than they shield boys and men (P < .001). DISCUSSION: There was a sex-based difference in the frequency of gonadal shielding usage among the sample in this study. Also, supervisors providing accessible protocols and encouraging gonadal shielding can increase technologists' use of gonadal shielding. CONCLUSION: Gonadal shielding is the current Code of Federal Regulations standard, although most professional and scientific organizations support discontinuing shielding during abdominal and pelvic radiography examinations. Shielding of these areas is more likely to occur with the availability of gonadal shielding, supervisory encouragement, protocols mandating shielding, and state regulations.

On methods for radiometric surveying in radiotherapy bunkers.

Radiometric surveys in radiotherapy bunkers have been carried out in Brazil for many years, both by the same radiotherapy facility for verification of shielding as by the regulatory agency for licensing and control purposes. In recent years, the Intensity Modulated Radiation Therapy (IMRT) technique has been gradually incorporated into many facilities. Therefore, it has been necessary to consider the increased leakage component that has an important impact on the secondary walls. For that, a radiometric survey method has been used that considers an increased 'time of beam-on' for the secondary walls. In this work we discuss two methods of doing this: the first considers that this 'time of beam-on' affects the sum of the two components, leakage and scattered. In another method it is considered that only the leakage component is affected by this extended 'time of beam-on'. We compare the methods and show that for secondary walls withU= 1 the first method overestimates dose rates by important percentages and for secondary walls withU< 1 it can both overestimate or underestimate the dose rates, depending on the parameters of the project. An optimized procedure is proposed, according to the use factor (U) of the secondary wall to be measured.

Radiation protection in CT-guided interventions: does real-time dose visualisation lead to a reduction in radiation dose to participating radiologists? A single-centre evaluation.

AIM: To evaluate if real-time dose visualisation during computed tomography (CT)-guided interventions leads to a reduction in radiation dose to participating radiologists. MATERIALS AND METHODS: The individual radiation dose radiologists are exposed to during CT interventions was measured using dedicated dosimeters (RaySafe i2-system, Unfors RaySafe GmbH, Billdal, Sweden) worn over the usual radiation protective apron. Initially, only the total radiation dose was measured, without visualisation (control group). In the following study period, the radiation dose was shown to participants on a live screen in real-time (experimental group). In both groups, the dose was recorded in 1-second intervals. The results collected were evaluated by comparison using descriptive statistics and mixed-effect models. In particular, the variables experience, gender, role, and position during the intervention were analysed. RESULTS: In total, 517 measurements of 304 interventions (n=249 with and n=268 without live screen) performed by 29 radiologists acting as interventionalists or assistants were analysed. All CT-guided interventions were performed percutaneously, the majority of which (n=280) were microwave ablations (MWA). Radiation doses in the group without visualisation were comparable with usual dose rates for the corresponding intervention type. The mean total radiation dose was reduced by 58.1% (11.6 versus 4.86 µSv) in the experimental group (p=0.034). The highest reduction of 78.5% (15.55 versus 3.35 µSv) was observed in radiologists with the role of assistant (p=0.002). Sub-analysis showed significant dose reduction (p<0.0001) for the use of live screen in general; considering all variables, the role "assistant" alone had a statistically significant influence (p=0.002). CONCLUSION: The real-time visualisation of active radiation dose during CT interventions leads to a relevant reduction in radiation dose to participating radiologists.

Radiation dose reduction during venous access port implantation: the importance of upgrading equipment and radiation-protection training.

BACKGROUND: Implantable central venous port systems are widely used in oncology. We upgraded our fluoroscopy machines, and all anesthetists completed two training courses focusing on the risks of ionizing radiation for patients and health workers. AIMS: This study aimed to evaluate the impact of upgrading the machines and the radiation-protection training on ionizing radiation exposure during venous port system implantation. METHODS: We retrospectively analyzed consecutive venous port implantations between 2019 and 2022. The older fluoroscopy machines were replaced by two new machines. A first training session about health worker radioprotection was organized. The medical staff completed a second training course focused on protecting patients from ionizing radiation. We defined four distinct time intervals (TI): venous port implantations performed with the old equipment, the new fluoroscopy machines, after the first training course, and after the second training course. The air kerma-area product (KAP) was compared between these four TI and fluoroscopy times and the number of exposures only with the new machines. RESULTS: We analyzed 2587 procedures. A 93% decrease in the median KAP between the first and last TI was noted (median KAP = 323.0 mGy.cm2 vs. 24.0 mGy.cm2, p < 0.0001). A decrease in the KAP was observed for each of the 11 anesthetists. We also noted a significant decrease in the time of fluoroscopy and the number of exposures. CONCLUSIONS: Upgrading the fluoroscopy equipment and completing two dedicated training courses allowed for a drastic decrease patient exposure to ionizing radiation during venous access port implantation by non-radiologist practitioners.

Radiation shielding assessment for interventional radiology personnel: Geant4 dosimetry of lead-free compositions.

The inherent biological hazards associated with ionizing radiation necessitate the implementation of effective shielding measures, particularly in medical applications. Interventional radiology, in particular, poses a unique challenge as it often exposes medical personnel to prolonged periods of high x-ray doses. Historically, lead and lead-based compounds have been the primary materials employed for shielding against photons. However, the drawbacks of lead, including its substantial weight causing personnel's inflexibility and its toxicity, have raised concerns regarding its long-term impact on both human health and the environment. Barium tantalate has emerged as a promising alternative, due to its unique attenuation properties against low-energy x-rays, specifically targeting the weak absorption area of lead. In the present study, we employ the Geant4 Monte Carlo simulation tool to investigate various formulations of barium tantalate doped with rare earth elements. The aim is to identify the optimal composition for shielding x-rays in the context of interventional radiology. To achieve this, we employ a reference x-ray spectrum typical of interventional radiology procedures, with energies extending up to 90 keV, within a carefully designed simulation setup. Our primary performance indicator is the reduction in air kerma transmission. Furthermore, we assess the absorbed doses to critical organs at risk within a standard human body phantom protected by the shield. Our results demonstrate that specific concentrations of the examined rare earth impurities can enhance the shielding performance of barium tantalate. To mitigate x-ray exposure in interventional radiology, our analysis reveals that the most effective shielding performance is achieved when using barium tantalate compositions containing 15% Erbium or 10% Samarium by weight. These findings suggest the possibility of developing lead-free shielding solutions or apron for interventional radiology personnel, offering a remarkable reduction in weight (exceeding 30%) while maintaining shielding performance at levels comparable to traditional lead-based materials.